Our long-term objective is to investigate central nervous system (CNS) mechanisms controlling the onset of puberty, particularly in female primates. We are interested in the extent to which the CNS is involved in the preovulatory release of luteinizing hormone (LH) necessary for ovulation. Our specific aim, therefore, is to clarify the participation of the CNS in the generation of the cyclic preovulatory LH release. The relative contributions of estradiol-1Beta, progesterone, and gonadotropin-releasing hormone, components of this system that influence the pituitary release of LH, will be investigated in an in vivo system in which CNS influences can be ruled out. The animal model for the proposed research is the female rhesus macaque with a transected pituitary stalk and an impermeable barrier between the hypothalamus and pituitary. In this model we can study the role of the pituitary and CNS by replacing various CNS influences. Electrical stimulation of separate hypothalamic areas in juvenile monkeys will also be performed to locate those areas that can, when stimulated, result in growth and rupture of the follicle. A clearer understanding of the degree to which the CNS participates in the acute signal for ovulation will contribute to development of safe, effective, and reversible methods to control fertility as well as to diagnose problems related to infertility. We must understand the nature of the CNS participation in preovulatory LH release in order to investigate how that capability develops during sexual maturation.